geo_lab_portfolio_for_spring_2015fandomcom-20200215-history
Visual Classification and Microscopy
Visual Classification Methodology ''' It is often necessary to determine the behavior of the soil you will build on but lab testing can be expensive so observing the physical properties of the soil through visual classification can help determine if a soil is adequate before subjecting it too costly and time consuming tests. To perform this lab a soil sample is tested for angularity, shape, color, odor, moisture, condition, range of particle sizes, hardness, and dispensability. This data is to be collected through examination using the five sense and manual test to gain an appraisal of a soil sample and more extensive testing should be performed to determine the behavior of the soil. '''Visual classification lab results Angularity: After touching the soil it was determined that there was some resistance between the moving grains indicating that the surfaces are most likely unpolished to the naked eye the grains where small and rounded with some large enough to see the angularity. Shape: There where no particles of significant size in the soil to judge. Color: The soil was moist and had a light brown and grey color . Odor: The soil had no unusual smells almost odorless Moisture condition: The soil was cold and dry to the touch with no visible free water Range of particle sizes: After allowing the sample in the stoppered test tube settle the majority of the soil over 90% precipitated out immediately leavening a very thin layer of silts deposited within 5 minutes. Hardness: The sand was relatively small but could not be broken with fingernails but could be crushed between my teeth with effort. Dispensability: The soil separated into layers almost immediately indicating a large percentage of sands with almost no silts and clays. Additional comments: The soil also appeared to have some adhesion between the particles in its moist condition but just barely forming a sheen on the surface. The angle of repose was not calculated from creating a loos pile of the soil but the pile that was made was small and had a shallow slope indicating a small angle of repose. USCS Classification of soils for grain size Distribution # 95% Sand > 1% Gravel # 4%<5% Passing the #200 Sieve # CU<6 # Gravel<15% # Using figure 5.7 PG.178 The soil would fall in the poorly-graded Sand USCS Classification of soils for Visual Classification ' # No Gravel # Mostly sand # Less than 5% silts and clays # Using figure 5.7 PG.178 The soil would fall in the poorly-graded Sand '''Microscopic Analysis ' 'Methodology ' Microscopic analysis is used in conjunction with the visual classification lab to further examine the physical properties of the soil. For this lab we used the digiblue microscope to examine the soil at magnifications of x10, x60, and x200. 'Observations ' '''Angularity: The angularity can be best seen in figure two showing that there are flat sides but the edges are well rounded with relatively plane faces making it a sub angular soil. Roughness: At x200 magnification the soil appears to have a smooth edges and ruff surfaces texture. Color: The soil was moist and had a grayish brown color at x10 magnification but at higher magnifications it becomes more opaque like glass. Range of particle sizes: The particles appear to be mostly sand with some silicates present at x200 magnification. Additional comments: ''' The soil also appeared to have some some clear crystalline particles in it almost like glass. '''Microscopic Images Figure One: Microscope Images at x 10 Magnifications Figure Two: Microscope Images at x 60 Magnifications Figure Three: Microscope Images at x 200 Magnifications Works Citation Coduto, Donald. P, Yeung, Man-cho. R., and Kitch, William. A. (2010). "5.3 Unified Soil Classification System (USCS)" Geotechnical Engineering Principles and Practices, Second Edition, chapter , 171-180